The question of whether the age of accountability is taught in the Bible has recently been a hot topic. It gets serious when someone asserted that children 19 years and below are assured of heaven regardless of the sins they committed because God winked at them anyway. Is this Biblical? What does the Bible have to say about it?
As obedient Bible students, we can discern that the Bible makes no mention of the precise age of accountability for sin, just as it makes no mention of when Jesus will return. Therefore, we must use caution when sharing our views or opinions on this matter. For we are told in the book of Deuteronomy:
Deuteronomy 29:29 “The secret things belong unto the LORD our God: but those things which are revealed belong unto us and to our children for ever, that we may do all the words of this law.”
In other words, because the Lord never revealed the exact age of accountability to us, no one can tell the exact age when a child is accountable for his sin and no one can say that children aged 19 years old and below are guaranteed to enter heaven since only God knows who will be saved or not. Salvation is solely God’s prerogative. In this matter, silence is eloquence.
A child’s moral and intellectual growth differs from one child to another. For example, two children who are eight years old may differ in intelligence and maturity. One learns quickly, while the other takes longer. One knows better than the other. As a result, each child is unique and this holds true for everyone.
What is the significance of Age 20? It is the minimum requirement for military and temple services.
The Bible clearly states that the age of 20 is the minimum requirement for military service and temple services. It has no other significance besides this.
Military Service
Numbers 1:3 “From twenty years old and upward, all that are able to go forth to war in Israel: thou and Aaron shall number them by their armies.”
2 Chronicles 25:5 "Moreover Amaziah gathered Judah together, and made them captains over thousands, and captains over hundreds, according to the houses of their fathers, throughout all Judah and Benjamin: and he numbered them from twenty years old and above, and found them three hundred thousand choice men, able to go forth to war, that could handle spear and shield."
Temple Service
1 Chronicles 23:24 "These were the sons of Levi after the house of their fathers; even the chief of the fathers, as they were counted by number of names by their polls, that did the work for the service of the house of the LORD, from the age of twenty years and upward".
Numbers 8:24-25 “This is it that belongeth unto the Levites: from twenty and five years old and upward they shall go in to wait upon the service of the tabernacle of the congregation: And from the age of fifty years they shall cease waiting upon the service thereof, and shall serve no more:”
Retirement from service
Please keep in mind that a Levite had to retire from the service at the age of 50. Does this mean that he also stops to be accountable in sin at the age of 50? Obviously not! This implies that the age restriction of 25-50 only applies to temple services because the nature of the work demands physical effort.
Is that an "Immortality of the soul" or “Once saved always saved” Version?
When someone teach and conclude that the children under the age of 20 are NOT accountable for their sins and are assured of heaven is of one’s “private interpretation”. Therefore, it is dangerous!
Remember, that “sin is the transgression of the law.” 1 John 3:4 and “the wages of sin is death” according to Romans 6:23.
So, how does this teaching differ from the serpent’s teaching in Genesis 3:4 that “ye shall NOT surely die” which is the false doctrine of immortality of the soul. Are we hearing a subtle message, a version of “once saved always saved” because the children ages 19 and below is always under grace? The apostle Paul says in Romans 6:15, “What then? shall we sin, because we are not under the law, but under grace? God forbid.”
The truth is that no sin, in any shape and form, will be permitted to enter in heaven.
Revelation 21:27 “And there shall in no wise enter into it any thing that defileth, neither whatsoever worketh abomination, or maketh a lie: but they which are written in the Lamb's book of life.”
“The great original lie which he (Satan) told to Eve in Eden, "Thou shalt not surely die," was the first sermon ever preached on the immortality of the soul. This sermon was crowned with success, and terrible results followed. He has brought minds to receive that sermon as truth, and ministers preach it, sing it, and pray it. No literal Devil, and probation after the coming of Christ, are fast becoming popular fables. The Scriptures plainly declare every person's destiny forever fixed at the coming of the Lord. Revelation 22:11, 12: "He that is unjust, let him be unjust still; and he which is filthy, let him be filthy still; and he that is righteous, let him be righteous still; and he that is holy, let him be holy still. And behold I come quickly; and my reward is with me, to give every man according as his work shall be." RH, May 13, 1862 par. 6}
1) The Men of War and David
Only men aged 20 years old and up were eligible to fight in the war.
However, David was only a youth when he was allowed by King Saul the opportunity to fight and slay the man of war, Goliath.
Why was David allowed to fight if he was only a youth and immature? Because young David has faith and those soldiers do not.
2) The Levites and Samuel
Only those Levites who were 20 or 25 years old could begin performing service of the tabernacle.
However, Samuel began to serve in the tabernacle as a child.
According to the Spirit of Prophecy, Samuel began his service in the tabernacle when he was just 12 years old.
Why was the young Samuel permitted to serve in the tabernacle despite the fact that there was an age requirement? Because Samuel is an exception to this rule.
3) Moses as a child has understanding heart
Moses was about 12 years old when separated from his parents but had a clear intellect.
The Spirit of Prophecy provided more information about his youth:
“The instructions he received from his parents were such as to fortify his mind, and shield him from being lifted up and corrupted with sin, and becoming proud amid the splendor and extravagance of court life. He had a clear mind, and an understanding heart, and never lost the pious impressions he received in his youth. His mother kept him as long as she could, but was obliged to separate from him when he [Moses] was about twelve years old, and he then became the son of Pharaoh's daughter.” - 1SP 164.1
4) Jesus as a child was a perfect pattern for all youth
Jesus when 12 years old was understanding and wise beyond his years.
Luke 2:42 “And when he was twelve years old, they went up to Jerusalem after the custom of the feast.”
Luke 2:40 “And the child grew, and waxed strong in spirit, filled with wisdom: and the grace of God was upon him.”
Luke 2:52 “And Jesus increased in wisdom and stature, and in favour with God and man.”
The Spirit of Prophecy revealed more details about his youth:
5) The Atonement Money and Judgment between the young and the old
Only those who were twenty years old and above had to give the ransom or atonement money of half shekel for the service of the tabernacle.
However, a young man in his youth was instructed to put away sinful lusts and follies because God will account for them in judgment.
This implies that everyone, young and old, has a record books in heaven where they will be judged based on their works.
Messages to Young People
Timothy as young man was exhorted by Paul to set a good example for believers.
The apostle John wrote to young men that they have overcome the wicked one.
Examples of Kings who reigned as boys and young men
NOTE: The above comparisons and examples demonstrate that young children aged seven to eighteen are old enough to discuss about their own religious duty.
1) Children ages eight to eighteen are old enough to be addressed about personal religion
“The mother's work commences with the infant. She should subdue the will and temper of the child, and bring its disposition into subjection. Learn it to obey. As the child grows older, relax not the hand. Every mother should take time to reason with the child, to correct its errors, and patiently teach it the right way. Christian parents should know that they are instructing and fitting their children to become children of God. The whole religious experience of the children is influenced by the instructions given, and character formed, in childhood. If the child's will is not subdued and made to yield in childhood to the will of the parents, then what a task! What a severe struggle! What a conflict, to yield that will which never was subdued, to the requirements of God! Parents who neglect this important work, commit a great error, and sin against their poor children, and against God. Children, while under strict discipline, will at times have dissatisfied feelings. They will feel impatient under restraint, and will wish to have their own will, and go and come as they please. And they will often feel, from the ages of ten to eighteen, that there would be no harm in going to picnics and other gatherings of young associates; yet their experienced parents can see danger. They are acquainted with the peculiar temperaments of their children, and know the influence of these things upon their minds, and in reference to their salvation, keep them back from these exciting amusements.” - 4bSG 132.3
“Parents should explain and simplify the plan of salvation to their children, that their young minds may comprehend it. Children of eight, ten, or twelve years of age, are old enough to be addressed on the subject of personal religion. Do not teach your children with reference to some future period, when they shall be old enough to repent and believe the truth. Very young children, if properly instructed, may have correct views of their state as sinners, and of the way of salvation through Christ. Ministers are generally too indifferent to the salvation of children, and are not personal as they should be. Golden opportunities to impress the minds of children frequently pass without being improved.” - 4bSG 142.2
“How many toil-worn, burdened parents have become slaves to their children, while, in harmony with their education and training, the children live to please, amuse, and glorify themselves. Parents sow the seed in the hearts of their children which yields a harvest that they do not care to reap. Under this training, at the age of ten, twelve, or sixteen, children think themselves very wise, imagine that they are prodigies, and regard themselves as altogether too knowing to be in subjection to their parents, and too elevated to stoop to the duties of everyday life. The love of pleasure controls their minds, and selfishness, pride, and rebellion work out their bitter results in their lives. They accept the insinuations of Satan, and cultivate an unhallowed ambition to make a great show in the world.” - YI, July 20, 1893 par. 6
2) Ellen White as youth was converted and baptized
“At the age of eleven years I was converted, and when twelve years old was baptized, and joined the Methodist Church. At the age of thirteen I heard Bro. Miller deliver his second course of lectures in Portland, Me. I then felt that I was not holy, not ready to see Jesus. And when the invitation was given for church members and sinners to come forward for prayers, I embraced the first opportunity, for I knew that I must have a great work done for me to fit me for Heaven. My soul was thirsting for full and free salvation, but knew not how to obtain it.” - RH, July 21, 1851 par. 2
3) A son who was stubborn, rebellious, glutton and drunkard was stoned to death
The Spirit of Prophecy has commented that the condition of this glutton son was considered hopeless.
“Overeating is the sin of this age. {4T 454.2} The word of God places the sin of gluttony in the same catalogue with drunkenness. So offensive was this sin in the sight of God that He gave directions to Moses that a child who would not be restrained on the point of appetite, but would gorge himself with anything his taste might crave, should be brought by his parents before the rulers in Israel and should be stoned to death. The condition of the glutton was considered hopeless. He would be of no use to others and was a curse to himself. No dependence could be placed upon him in anything. His influence would be ever contaminating others, and the world would be better without such a character; for his terrible defects would be perpetuated. None who have a sense of their accountability to God will allow the animal propensities to control reason. Those who do this are not Christians, whoever they may be and however exalted their profession. The injunction of Christ is: "Be ye therefore perfect, even as your Father which is in heaven is perfect." Matthew 5:48 He here shows us that we may be as perfect in our sphere as God is in His sphere.” - 4T 454.3
In addition, the “rebellious son” in this text is applied to both young and old and should be cut off from the congregation.
“Fond and indulgent parents, let me present for your instruction the directions given in the Bible for dealing with a rebellious son: [quoted Deuteronomy 21:18-21]… Both the young and the old who are connected with the office should be looked after closely, lest their influence should be such as to work directly against the object designed by the office. If any are employed whose influence is of a character to lead away from God and the truth, there should not be a moment's question as to the disposal of their cases. They should be separated from the office at once, for they are scattering from Christ instead of gathering with Him. They are virtually servants of Satan.” - 4T 205.1
4) A young girl who breaks the seventh commandment did not commit a sin of ignorance and will face God’s wrath
“Those who break the seventh commandment should be suspended from the church and not have its fellowship or the privileges of the house of God. Said the angel, “This is not a sin of ignorance. It is a knowing sin and will receive the awful visitation of God, whether he who commits it be old or young.” Never was this sin regarded by God as being so exceedingly sinful as at the present time. Why? Because God is purifying unto Himself a peculiar people, zealous of good works. It is at the very time when God is purifying this peculiar people unto Himself that [unsanctified] individuals step in among us. Notwithstanding the straight truths they have heard, the terrors of the Word of God set before them, and all the blazing truth for these last days calculated to arouse Israel—they sin with a high hand, give way to all the loose passions of the carnal heart, gratify their animal propensities, disgrace the cause of God, and then confess they have sinned and are sorry! And the church receives them and says “Amen” to their prayers and exhortations, which are a stink in the nostrils of God and cause His wrath to come upon the camp. He will not dwell in their assemblies. Those who move on thus heedlessly, plastering over these sins, will be left to their own ways, to be filled with their own doings. Those who anciently committed these sins were taken without the camp and stoned to death. Temporal and eternal death was their doom; and because the penalty of stoning to death is abolished, this sin is indulged in beyond measure, and is thought to be a small offense.” - Manuscript 3, 1854, February 12, 1854
DEATH PENALTY HAS BEEN ABOLISHED AND REPLACED BY CHURCH DISCIPLINE
Despite the fact that the death penalty was abolished after the cross, we still serve the same God today.
“We serve the same God today. But the death penalty has been abolished; had it not been, there would not now be so much careless, disorderly work in His cause.” - 5T 274
“Those who anciently committed these sins were taken without the camp and stoned to death. Temporal and eternal death was their doom; and because the penalty of stoning to death is abolished, this sin is indulged in beyond measure and is thought to be a small offense.” - Manuscript 3, 1854
However, in the New Testament, sin is punished through cutting off or church discipline.
“The world's Redeemer has invested great power with His church. He states the rules to be applied in cases of trial with its members. After He has given explicit directions as to the course to be pursued, He says: "Verily I say unto you, Whatsoever ye shall bind on earth shall be bound in heaven: and whatsoever [in church discipline] ye shall loose on earth shall be loosed in heaven." [Matthew 18:18] Thus even the heavenly authority ratifies the discipline of the church in regard to its members when the Bible rule has been followed. The word of God does not give license for one man to set up his judgment in opposition to the judgment of the church, neither is he allowed to urge his opinions against the opinions of the church. If there were no church discipline and government, the church would go to fragments; it could not hold together as a body.” - 3T 428
5) Elisha and the wicked children
“As the people of God united in the cry of the second angel, the heavenly host marked with the deepest interest the effect of the message. They saw many who bore the name of Christians turn with scorn and derision upon those who had been disappointed. As the words fell from mocking lips, "You have not gone up yet!" an angel wrote them. Said the angel, "They mock God." I was pointed back to a similar sin committed in ancient times. Elijah had been translated to heaven, and his mantle had fallen upon Elisha. Then wicked youth, who had learned from their parents to despise the man of God, followed Elisha, and mockingly cried, "Go up, thou bald head; go up, thou bald head." In thus insulting His servant, they insulted God and met their punishment then and there. In like manner, those who have scoffed and mocked at the idea of the saints' going up, will be visited with the wrath of God, and will be made to feel that it is not a light thing to trifle with their Maker.” - EW 247.2
“I was pointed back to the translation of Elijah. His mantle fell on Elisha, and wicked children (or young people) followed him, mocking, crying, Go up thou bald head! Go up thou bald head! They mocked God, and met their punishment there. They had learned it of their parents. And those who have scoffed and mocked at the idea of the saints' going up, will be visited with the plagues of God, and will realize that it is not a small thing to trifle with him.” - 1SG 154.1
6) The angel of death to slay old and young without the mark
“The mark of deliverance has been set upon those “that sigh and that cry for all the abominations that be done.” Now the angel of death goes forth, represented in Ezekiel's vision by the men with the slaughtering weapons, to whom the command is given: “Slay utterly old and young, both maids, and little children, and women; but come not near any man upon whom is the mark; and begin at my sanctuary.” Says the prophet, “They began at the ancient men which were before the house.” [Ezekiel 9:6.] The work of destruction begins among those who profess to be the spiritual guardians of the people. The false shepherds are the first to fall. There are none to pity or to spare. Men, women, maidens, and little children perish together.” - 4SP 472.3
“Children are the lawful prey of the enemy, because they are not subjects of grace, have not experienced the cleansing power of the blood of Jesus, and the evil angels have access to these children; and some parents are careless and suffer them to work with but little restraint.” RH September 19, 1854
7) Ellen White’s 16 years old son put his full trust in Jesus before he died.
“As you relate your experience in the death of your child, and how you bowed in prayer, submitting your will to the will of your heavenly Father, leaving the matter with Him, my mother heart is touched. I have passed through an experience similar to the experience through which you have just passed.
“When my eldest son was sixteen years old, he was stricken down in sickness. His case was considered critical, and he called us to his bedside, and said, “Father, Mother, it will be hard for you to part with your eldest son. If the Lord sees fit to spare my life, for your sake I will be pleased. If it is for my good and His name's glory for my life to close now, I will say, It is well with my soul. Father, go by yourself, and Mother, go by yourself; and pray. Then you will receive an answer according to the will of my Saviour, whom you love and I love.” He was afraid that if we should bow together, our sympathies would strengthen, and we would ask for that which it would not be best for the Lord to grant.
“We did as he requested, and our prayers were similar in every point to the prayers you offered. We received no evidence that our son would recover. He died, putting his full trust in Jesus our Saviour. His death was a great blow to us, but it was a victory even in death; for his life was hid with Christ in God.
“Before the death of my eldest boy, my babe was sick unto death. We prayed, and thought that the Lord would spare us our darling; but we closed his eyes in death, and laid him away to rest in Jesus, until the Life-giver shall come to awaken His precious loved ones to a glorious immortality.
“Then my husband, the faithful servant of Jesus Christ, who had stood by my side for thirty-six years, was taken from me, and I was left to labor alone. He sleeps in Jesus. I have no tears to shed over his grave. But how I miss him! How I long for his words of counsel and wisdom! How I long to hear his prayers blending with my prayers for light and guidance, for wisdom to know how to plan and lay out the work!
“But the Lord has been my Counselor, and the Lord will give you grace to bear your bereavement.
Many little ones like babies and infants will be laid away before the time of trouble
“You inquire in regard to your little one's being saved. Christ's words are your answer: “Suffer little children to come unto Me, and forbid them not: for of such is the kingdom of God” (Luke 18:16).
“Remember the prophecy, “Thus saith the Lord; A voice was heard in Ramah, lamentation, and bitter weeping; Rahel weeping for her children refused to be comforted.... Thus saith the Lord; Refrain thy voice from weeping, and thine eyes from tears: for thy work shall be rewarded, saith the Lord; and they shall come again from the land of the enemy. And there is hope in thine end, saith the Lord, that thy children shall come again to their own border” (Jeremiah 31:15-17).
“This promise is yours. You may be comforted and trust in the Lord. The Lord has often instructed me that many little ones are to be laid away before the time of trouble. We shall see our children again. We shall meet them and know them in the heavenly courts. Put your trust in the Lord, and be not afraid.” - Letter 196, 1899, November 27, 1899 (Letter to Sister Robinson) (Also found in 2SM 258-259)
8) Children of Unbelieving Parents Be Saved?
“I had some conversation with Elder [J.G.] Matteson in regard to whether children of unbelieving parents would be saved. I related that a sister had with great anxiety asked me this question, stating that some had told her that the little children of unbelieving parents would not be saved. This we should consider as one of the questions we are not at liberty to express a position or an opinion upon, for the simple reason that God has not told us definitely about this matter in His Word. If He thought it was essential for us to know, He would have told us plainly. The things He has revealed are for us and for our children. There are things we do not now understand. We are ignorant of many things that are plainly revealed. When these subjects which have close relation to our eternal welfare are exhausted, then it will be ample time to consider some of these points that some are unnecessarily perplexing their minds about.”
The faith of believing parents extends to their children and covers them from destroying angel
“I know that some questioned whether the little children of even believing parents should be saved, because they have had no test of character and all must be tested and their character determined by trial. The question is asked, "How can little children have this test and trial?" I answer that the faith of the believing parents covers the children, as when God sent His judgments upon the first-born of the Egyptians.”
“God sent a word of comfort to the bereaved mothers of Bethlehem that the weeping Rachels should see their children coming from the land of the enemy. Christ took little children in His arms and blessed them and rebuked the disciples who would send away the mothers, saying, "Suffer little children, and forbid them not, to come unto me: for of such is the kingdom of heaven" (Matthew 16:14) Christ blessed the children brought to Him by the faithful mothers. He will do this now if mothers will do their duty to their children and teach their children and educate them in obedience and submission. Then they will bear the test and will be obedient to the will of God, for parents stand in the place of God to their children.”
Unruly children would not be taken to heaven
“Some parents allow Satan to control their children, and their children are not restrained, but are allowed to have wicked tempers, to be passionate, selfish, and disobedient. Should they die these children would not be taken to heaven. The parent's course of action is determining the future welfare of their children. If they allow them to be disobedient and passionate they are allowing Satan to take them in charge and work through them as shall please his satanic majesty, and these children, never educated to obedience and to lovely traits of character, will not be taken to heaven, for the same temper and disposition would be revealed in them.
We cannot tell if the children of unbelieving parents will be saved
“I said to Brother Matteson. Whether all the children of unbelieving parents will be saved we cannot tell, because God has not made known His purpose in regard to this matter, and we had better leave it where God has left it and dwell upon subjects made plain in His Word. This is a most delicate subject. Many unbelieving parents manage their children with greater wisdom than many of those who claim to be children of God. They take much pains with their children, to make them kind, courteous, unselfish and to teach them to obey, and in this the unbelieving show greater wisdom than those parents who have the great light of truth but whose works do not in any wise correspond with their faith.“ - Manuscript 26, 1885. Diary, October 22, 1885 (Also found in 3SM 313-315)
Bible Texts about the importance of training their children while young:
God command parents to train their children in the way of the Lord while their children are still young and there is still hope. Because of our sinful nature and the child’s natural and hereditary tendency, his or her ways are always in the opposite direction, that is, against God. For example, a child needs to be taught to keep and obey the law as well as to tell the truth. But a child doesn’t need to be taught to break and disobey the law or to lie because it comes naturally because of sinful nature. But when sin or wrong is committed, it should not be ignored, but should be restrained, corrected and led them to Christ for forgiveness. Yes, when parents fulfill their God-given duty faithfully to train up their children in God’s way while there is still hope, the seeds are planted in their hearts. However, it is not a guarantee that a good parent will have a good child or vice versa; for it is possible to be a good parent and have an evil child, and an evil parent to have a good child. For example, a good Adam and an evil Cain; An evil King Saul and a good Jonathan.
God cannot cover iniquity in children
“Parents stand in the place of God to their children and they will have to render an account, whether they have been faithful to the little few committed to their trust. Parents, some of you are rearing children to be cut down by the destroying angel, unless you speedily change your course, and be faithful to them. God cannot cover iniquity, even in children. He cannot love unruly children who manifest passion, and he cannot save them in the time of trouble. Will you suffer your children to be lost through your neglect? Unfaithful parents, their blood will be upon you, and is not your salvation doubtful with the blood of your children upon you? children that might have been saved had you filled your place, and done your duty as faithful parents should.” - RH September 19, 1854, par. 4
Where is your beautiful flock?
Many unfaithful parents who neglected to train their children in the ways of the Lord will meet a sad ending when they face this question, “where is the flock that was given thee, thy beautiful flock?” Jeremiah 13:20.
But the faithful parents will be happy and will be able to say, “here am I and the children you gave me” - “Behold, I and the children whom the Lord hath given me”. Isaiah 8:18
THE BOTTOM LINE:
The Bible and Spirit of Prophecy agree and made it clear that God has not revealed the age of accountability to us, and we should leave it where God has left it and dwell only on the subjects He has made plain in His word. Let us not dwell on subjects that are not essential to salvation. Our burden is to preach the last message of mercy to the perishing world. The present truth is what the flock needs now.
“I saw the necessity of the messengers, especially, watching and checking all fanaticism wherever they might see it rise. Satan is pressing in on every side, and unless we watch for him, and have our eyes open to his devices and snares, and have on the whole armor of God, the fiery darts of the wicked will hit us. There are many precious truths contained in the Word of God, but it is “present truth” that the flock needs now. I have seen the danger of the messengers running off from the important points of present truth, to dwell upon subjects that are not calculated to unite the flock and sanctify the soul. Satan will here take every possible advantage to injure the cause. But such subjects as the sanctuary, in connection with the 2300 days, the commandments of God and the faith of Jesus, are perfectly calculated to explain the past Advent movement and show what our present position is, establish the faith of the doubting, and give certainty to the glorious future. These, I have frequently seen, were the principal subjects on which the messengers should dwell.” {EW 63.2}
Psalms 91:4 “He shall cover thee with his feathers, and under his wings shalt thou trust: his truth shall be thy shield and buckler.”
I hope and pray that your are blessed!
From pastor Nic’s desk: Q & A #292
Question #292: What is the age of accountability?
Ok so --- I read the Scriptures…and didn’t see that the AGE OF ACCOUNTABILTY WORDING in any of it…other than it being INFERRED OR ASSUMED…that by age 20 they’d be PHYSICALLY READY….but I missing something ? what about spiritually ready? The age of Spiritual Accountability - meaning “right with God” or “saved” from the wrath of God, if you will….
You had said at one point that God made the age 20 (per those verses you shared) because by this time these men would be able to “accept God” and therefore be SAFE/SAVED in battle. I guess the Question they may ask is HOW can you KNOW THE AGE God SAYS? (and I don’t see it in any Scripture not in the ones you sent either) many scholars say by the age of 13 (bar/bat) a child should know better and therefore if you have heard the Gospel and reject it (Him), you’d be separated from God forever -- bc you had not accepted Jesus by faith. – meaning for today not back then because Christ had not come yet. Ugh am I making sense?
ANSWER:
As I see it, and I base my findings on what I have found by feasting on the precepts, line upon line, here a little and there a little over the years; we have to remember that back then the believers were actually ready by the age of 13 and recognized by Jewish tradition as having the same rights as a full grown man once the ceremony was performed. In fact the bar mitzvah literally translates as "son of commandment." But common sense dictates, unless the boy had the faith of David, he was not likely to sign up for battle or even be able to fit in the armor of a soldier.
Seeing how a 13 year old boy was not going to be a good candidate for battle, and seeing how the age “20” was laid out in the Word regarding certain duties, it appears obvious that for them to be experienced in the spiritual adulthood I can only conclude that they needed more years of walking in the truth of the Torah that they already declared as truth at their bar mitzvah 7 years prior. A “hands on” experience was needed for them to grow further and therefore applied here I guess you can say.
Seeing how the Lord is the one that laid out the age of “20” multiple times in the Word for reasons one can only assume an adult can perform with confidence, I must base my definition using only that which I can find in His Word on any given topic. I am a firm believer in not adding to or taking away from His Word. After all, is it not written in Isaiah 28:9-10, "Whom shall he teach knowledge? and whom shall he make to understand doctrine? them that are weaned from the milk, and drawn from the breasts. For precept must be upon precept, precept upon precept; line upon line, line upon line; here a little, and there a little:"
That being said, I don’t think you will find a locked down verse that says “the age of accountability is 20” in the Word, any more than you can find a verse in the Bible that says the exact date of Christ’s return, even though we know He is coming back on one particular day. But when you see the men eventually had the ok from on High to actually die in battle at that age as well as all the other passages that declared the age of 20 to be a deciding factor in other essential duties in and for the Sanctuary, one can only understand that yes, age 20 is the actual physical and spiritual pinnacle every Jewish male back then hoped to reach so as to do as God would call him to do. It was obviously a different world back then.
BUT, and I only add this to prevent confusion if you dig into how some boys were educated, this does not include the Rabbinical students who could be rejected or accepted by their Mentor who, as the tradition goes, their Rabbi’s “dust was upon them” as they followed close behind day by day in their spiritual education. These chosen boys who were soon to be men hoped to become Rabbis and so it was up to the teacher as to if and when he was ready. They could be rejected before, during or after the age of 20 for any reason the Rabbi offered. And so I look at the Bar Mitsvah and the start of the education of the young men that will reach its pinnacle at age 20.
I must say, I pray you and I get literally covered in the dust of Christ’s sandals as we walk near Him day by day so as to reach the perfection in Christ only His bride can gain. :)